Like I said, if it's striking surface all the way down, then you'd probably have to make it thicker (unless the thinnest part of the flat is 2.5"). Considering you said that the front edge was striking, then you just need to worry about marking the non striking. However, at the same time, don't forget about double checking these:
4.1.5 - Two- and & a half-inch rule: Projectile weapon tips (arrows, javelins and rocks)
and melee weapon tips designed for stabbing (green sword points, spear tips, etc.) shall
not easily pass more than 0.5 inch through a 2.5 inch-diameter hole. This measurement
shall be conducted by lowering a testing template onto the tip of the weapon
perpendicular to the edge or shaft of the weapon. The intent is to test the thrusting tip of
the weapon, not to search for weapon head corners which can be manipulated to pass
through the template.
4.1.6 - Two-inch rule: Weapon tips NOT designed for thrusting (non-stabbing sword
points, flail haft tip, etc.) shall not easily pass more than 0.5 inch through a 2 inch
diameter hole. This measurement shall be conducted by lowering the testing template
onto the tip of the weapon perpendicular to the edge or shaft of the weapon. The intent is
to test the tip of the weapon, not to search for sword and axe head corners that can pass
through the template.
4.1.11.2.3 - Blue weapons must weigh a minimum of 12 ounces.
4.2.2 - Blue swords must have a minimum blade length of 12 inches from above the
handgrip to the tip and a maximum total length less than 48 inches.
If it passes all this fun stuff, then it's good in my book. Keep in mind though, there are checkers that interpret the rules as saying that there must be at least 12" of STRIKING SURFACE, not just blade, but actual striking surface. Like I said though, I go by the wording and spirit of the rules as much as possible.